Hákarl: Iceland's Fermented Shark, Explained

Hákarl is Iceland's fermented Greenland shark: pale, chewy cubes with a sharp ammonia smell, traditionally eaten on toothpicks and chased with a shot of brennivín. It is the country's most notorious food and a fixture of the midwinter Þorrablót feast. Behind the reputation is a practical reason for how it is made: fresh Greenland shark meat is toxic, and Icelanders learned to cure it into something that can be eaten.

This page explains what hákarl is, how it is made, what it tastes like and how to serve it. It is not a dish to attempt from scratch: hákarl should always come from a licensed Icelandic producer.

Serves 4 as a tasting · 10 minutes · No cooking (buy it ready-made)

What is hákarl?

Hákarl is made from the Greenland shark (Somniosus microcephalus), a large, slow-growing shark of the cold North Atlantic. The meat is cured by a long fermentation and then air-dried, and it is traditionally served in small cubes.

Why fresh Greenland shark is toxic, and how curing fixes it

Fresh Greenland shark meat is rich in urea and trimethylamine oxide (TMAO). A 2023 study in the journal Heliyon describes fresh or unprocessed meat as "considered toxic if consumed excessively" because of these ammonia-containing compounds. The traditional cure breaks them down.

A 2026 study of commercial hákarl found that TMAO was depleted early in fermentation and had fallen below the limit of quantification after five weeks. It also identified trimethylamine as the main compound behind the ammonia-like smell.

How hákarl is made

The classic method has changed little over the centuries. The shark is gutted and cut up, then fermented in a shallow pit of gravel or sand (or in a container) under weight, so that the fluids drain out. Fermentation takes six to twelve weeks, depending on the temperature and the season.

The meat is then cut into strips and hung to dry in a ventilated shed for several months, four to five in the classic account. What comes out is a firm, pale, ammonia-scented product that is cut into cubes for serving. The Bjarnarhöfn shark museum on the Snæfellsnes peninsula is a well-known place to learn how it is done.

What does hákarl taste like?

The smell is the first hurdle: sharp, ammonia-rich and fishy. The meat is firm and chewy. Reports of the taste are mixed: some people find it milder than the smell suggests, and others cannot finish a piece. A very small first bite, with a chaser ready, is the usual advice.

Ingredients

• 200 g ready-made hákarl (cubed), from a reputable Icelandic producer
• Rúgbrauð (dark rye bread), to serve alongside
• Brennivín (Icelandic schnapps), chilled, for the traditional chaser

Preparation

• Remove the hákarl from its packaging shortly before serving. The strong ammonia smell is normal.
• Cut into small bite-sized cubes and spear each with a toothpick.
• Serve at room temperature, on its own or on a small piece of rúgbrauð.
• Follow local custom: eat one cube, then chase it with a small shot of chilled brennivín.

Chef's tips

• Never attempt to ferment fresh shark meat at home. Improperly processed Greenland shark remains toxic and can cause serious illness. Always buy hákarl ready-made from a licensed Icelandic producer.
• First-timers do best with a very small piece and the brennivín chaser ready before tasting.
• Follow the storage instructions on the pack. Once opened, keep it in a sealed container in the fridge.
• Treat it as a tasting food and eat small portions.

When Icelanders eat hákarl

Hákarl is most closely linked with Þorrablót, the midwinter feast held in the month of Þorri, from late January into February, where it is served among the other þorramatur dishes such as hangikjöt, svið and harðfiskur. It is also sold in Icelandic shops and can be eaten year-round. The usual accompaniments are rúgbrauð and a shot of brennivín.

Is hákarl safe to eat?

Icelandic producers sell hákarl in shops and to visitors, and the traditional cure is designed to remove the toxic compounds. The risk lies in fresh or improperly processed shark, which is why it is cured for months and why home fermentation is a bad idea. If you are pregnant or have a medical condition, check with your doctor before trying fermented or cured fish products.

Sustainability

The Greenland shark grows slowly and lives a very long time, and the IUCN Red List classes it as Vulnerable. The consumption, hunting and bycatch of Greenland sharks has been criticised as unsustainable, so it is worth asking where a producer's shark comes from.

Where to try hákarl

You can buy ready-made hákarl in Icelandic supermarkets, taste it at restaurants and food events that serve þorramatur, and learn how it is made at the Bjarnarhöfn shark museum on Snæfellsnes.

Want to taste it the local way?

If you'd rather taste Icelandic food with someone explaining it on the spot, NordExplore lists food tours around Reykjavík, including the Reykjavík All In One Food Tour – Eat, Drink & Explore with Locals, a four-hour tour with stops for traditional Icelandic food, local pastries with coffee or tea, the famous hot dog stand and local fish with beer. The listing does not mention hákarl, so check with the operator if you want to try it. (Sponsored links.)

Hákarl FAQ

Why does hákarl smell like ammonia?

Mostly trimethylamine, which forms as the shark's TMAO breaks down during fermentation, according to a 2026 study of commercial hákarl.

How long does hákarl take to make?

Producers vary. Fermentation takes six to twelve weeks, followed by drying that lasts from several weeks to months.

What do you drink with hákarl?

Brennivín, an Icelandic schnapps, is the traditional chaser.

Sources

• Jensen et al., Heliyon (2023): Unlocking the microbial diversity and the chemical changes throughout the fermentation process of hákarl, Greenland shark
• Novel insights into hákarl: microbiological and physico-chemical features of Iceland's traditional fermented shark (2026), PubMed
• IUCN Red List: Somniosus microcephalus, Greenland shark
• Wikipedia: Hákarl (serving customs and Þorrablót)